Metallic



H. 1. JAEGER.

METALLIC FILAMENT LAMP.

.APPLICATION FILED SEPT. 22, |920.

S14/uen Loa llO Patented Nov. 28, 1922.

UNITED STATES PATENT OFFICE. -f

' HERMAN JAEGER, OE VJEEHAWKEN, NEW JERSEY, ASSIGNOR TO JAEGER RESEARCH LABORATORIES, INC.

METALLIC-FILAMENT LAMP.

Application filed September 22, 19x20. Serial No. 411,941.

To all whom it may concern:

Be it known that I, HERMAN J. JAEGER, a citizen of the United States of America, residing at Weehawken, in the county of Hudson and State of New Jersey, have 1nvented certain new and useful improvements in Metallic-Filament Lamps, of which the following is a specification.

This invention has reference to improvements in metallic filament lamps of the type which embody both a high and low candle power filament and has for its object to provide a construction which will considerably enhance the eiiiciency of the lamp.

According to this invention the lamp 1s provided with two low candle power filaments each carried in the usual manner by an outer lead and both connected in the focal centre to a central metallic anchor in form of a coiled wire which is adapted at times to serve merely as lead and at others to act as a third filament to produce in conjunction with the lateral filaments high candle power.

For low candle power either one of the two lateral filaments is thrown into circuit, whereby the possibility is given to continue the use of the lamp when one of the filaments is burnt out.

For high candle power both lateral filaf ments are thrown into circuit whereby the central wire is converted into a third filament, still more increasing the candle power.

In the accompanying drawing in which similar reference characters denote corresponding parts, Fig. 1 is an elevation partly in section of my new lamp; Figs. 2 to 4c are diagrammatic illustrations of the electric connections, Fig. 2 showino' the right hand filament with the central filament being in circuit for low candle power; Fig. 3 showing the left hand filament with the central filament being in circuit for low candle power, and Fig. 4 showing the two side filaments and central filament being in circuit for high candle power.

Referring to the drawing more in detail, a represents the globe,v b the stem or support; c, ci and e denote the leads which pass through the stem Z) parallel to each other and connect with short platinum wires c', d', e respectively in the usual manner. The other ends of these platinum wires are connected to ne conductive tubes f, g, la respectively, fused into the solid portion of the stem b. Conductively connected to the outer end ofthe tubes are three concentrated or coiled metallic wiresz', j and k of which the wire j forms a rectilinear extension of the central tube g terminating in the focal centre of the globe and serving normally as anchor for the two other wires z' and 7c which converge from their respective tubes f, 71. toward the focal centre and there are conductively connected to one another and to the wire The outer or lateral wires e', 7c are of uniform thickness and serve each for low candle power, while the central wire j is made of different thickness, so that when either one of the lateral wires is thrown into circuit to produce low candle power, said central wire will act merely as conductor, but when both lateral wires are thrown into circuit, it will be converted into a thirdfilament which, in conjunction with said lateral wires, will produce high candle power.

This construction enables the use of the lamp with either one of the lateral filaments for low candle power, so that when one is burnt out the other is still available. Furthermore, it also affords an economical utilization of the current by the arrangement of the third wire capable of acting at times as conductor and at others as filament.

What I claim and desire to secure by Letters Patent is:

l. n a metallic filament lamp, the combination with' the globe and three parallel leads, of three metallic wires extending from said leads and conductively connected to one another in the focal centre of the globe, the outer wires forming filaments of uniform rc- .sistance each to produce low candle power and the middle wire being of such resistance that when either of the outer filaments is thrown into circuit, said middle wire will act merely as lead and when both lateral filaments are thrown into circuit it will act as a third filament producing in conjunction with the same high candle power.

2. In a metallic filament lamp, the combination with the globe and three parallel. leads, of three metallic wires extending from said leads of which the middle one extends rectilinearly with its respective lead and terminates in the focal centre, and the lateral ones converge toward and are conductively connected to one another and to said middle wire in said focal centre, the outer wires constituting filaments of uniform resistance to serve each for low candle power vand the middle Wire being of such resistance In testimony whereof I affix my signature als't'act zlnrely as lead 1when either one ofY in presence of tWo witnesses.

tie atei'a aments is tn'own into circuit but to act v:Le additional ilament ywhen botli e HERMAN J' JAEGER" said lateral filaments are thrown into circuit Vitnesses:

so as to produce in conjunction with them M. JQJAEGER high candle power. n Lingen R. ASSEBAUM. 

